* ld -shared -Bsymbolic and C++ shared library
@ 2006-07-16 17:26 H. J. Lu
2006-07-27 22:37 ` Geoffrey Keating
0 siblings, 1 reply; 3+ messages in thread
From: H. J. Lu @ 2006-07-16 17:26 UTC (permalink / raw)
To: gcc; +Cc: binutils
ld -shared -Bsymbolic will reduce number of dynamic relocations in
a shared library. Unfortunately, it won't work correctly with C++
exception and maybe other language features.
However, I think it is possible to make -shared -Bsymbolic to work
for C++ by providing a way to specify a list of symbols which must
be dynamic. We then can do
# g++ -Wl,-Bsymbolic -shared -xxx "list of dynamic symbols" -o libfoo.so ...
and libfoo.so written in C++ will work correctly with much fewer dynamic
relocations.
H.J.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: ld -shared -Bsymbolic and C++ shared library
2006-07-16 17:26 ld -shared -Bsymbolic and C++ shared library H. J. Lu
@ 2006-07-27 22:37 ` Geoffrey Keating
2006-07-28 1:21 ` H. J. Lu
0 siblings, 1 reply; 3+ messages in thread
From: Geoffrey Keating @ 2006-07-27 22:37 UTC (permalink / raw)
To: H. J. Lu; +Cc: binutils, gcc
"H. J. Lu" <hjl@lucon.org> writes:
> ld -shared -Bsymbolic will reduce number of dynamic relocations in
> a shared library. Unfortunately, it won't work correctly with C++
> exception and maybe other language features.
>
> However, I think it is possible to make -shared -Bsymbolic to work
> for C++ by providing a way to specify a list of symbols which must
> be dynamic. We then can do
>
> # g++ -Wl,-Bsymbolic -shared -xxx "list of dynamic symbols" -o libfoo.so ...
>
> and libfoo.so written in C++ will work correctly with much fewer dynamic
> relocations.
You may find this would be easier to use if you just had a flag which
made -Bsymbolic apply only to non-weak symbols.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: ld -shared -Bsymbolic and C++ shared library
2006-07-27 22:37 ` Geoffrey Keating
@ 2006-07-28 1:21 ` H. J. Lu
0 siblings, 0 replies; 3+ messages in thread
From: H. J. Lu @ 2006-07-28 1:21 UTC (permalink / raw)
To: Geoffrey Keating; +Cc: binutils, gcc
On Thu, Jul 27, 2006 at 03:37:33PM -0700, Geoffrey Keating wrote:
> "H. J. Lu" <hjl@lucon.org> writes:
>
> > ld -shared -Bsymbolic will reduce number of dynamic relocations in
> > a shared library. Unfortunately, it won't work correctly with C++
> > exception and maybe other language features.
> >
> > However, I think it is possible to make -shared -Bsymbolic to work
> > for C++ by providing a way to specify a list of symbols which must
> > be dynamic. We then can do
> >
> > # g++ -Wl,-Bsymbolic -shared -xxx "list of dynamic symbols" -o libfoo.so ...
> >
> > and libfoo.so written in C++ will work correctly with much fewer dynamic
> > relocations.
>
> You may find this would be easier to use if you just had a flag which
> made -Bsymbolic apply only to non-weak symbols.
It doesn't work since
1. There are weak function symbols, which we do want to bind locally.
2. Weak symbols aren't required for comdat group.
BTW, -Wl,-Bsymbolic can't be used since it will add DF_SYMBOLIC to
shared library, which will cause dynamic linker to resolve symbols
locally.
H.J.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2006-07-16 17:26 ld -shared -Bsymbolic and C++ shared library H. J. Lu
2006-07-27 22:37 ` Geoffrey Keating
2006-07-28 1:21 ` H. J. Lu
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